Induction of Th17 differentiation by corneal epithelial‐derived cytokines

This study was to explore a potential role of epithelium‐derived cytokines in Th17 differentiation. Th17 induction was evaluated by murine CD4⁺ T cells treated with different combinations of five inducing cytokines, or conditioned media of human corneal epithelial cells (HCECs) exposed to a variety of stimuli. Th17 differentiation was determined by measuring Th17 associated molecules, IL‐17A, IL‐17F, IL‐22, CCL‐20, and STAT3 at mRNA and protein levels, and numbers of IL‐17‐producing T cells by real‐time PCR, and cytokine immunobead and ELISPOT assays, respectively. IL‐23 was the strongest inducer for expanding Th17 cells in the presence of TGF‐β1 + IL‐6; and IL‐1β was the strongest Th17 amplifier in the presence of TGF‐β1 + IL‐6 + IL‐23. These inducing cytokines were found to be significantly stimulated in HCECs challenged by hyperosmotic media (450 mOsM), microbial components (polyI:C, flagellin, R837, and other TLR ligands) and TNF‐α. Interestingly, when incubated with conditioned media of HCECs irritated by polyI:C or TNF‐α, CD4⁺ T cells displayed increased mRNA levels of IL‐17A, IL‐17F, IL‐22, CCL‐20, and STAT3, increased IL‐17 protein in the supernatant, and increased numbers of IL‐17‐producing T cells (Th17 cells). These findings demonstrate for the first time that Th17 differentiation can be promoted by cytokines produced by corneal epithelium that are exposed to hyperosmotic, microbial, and inflammatory stimuli. J. Cell. Physiol. 222:95–102, 2010. © 2009 Wiley‐Liss, Inc.     

Ageing exacerbates damage of systemic and salivary neutrophils from patients presenting Candida-related denture stomatitis

Background  

Ageing leads to a decline in the function of the immune system, increasing the body's susceptibility to infections through the impairment of T-cells, macrophages, neutrophils and dendritic cells Denture stomatitis is a primary oral disease affecting elderly denture wearers. The major etiologic factor involved in this pathology is the infection by Candida albicans, an opportunistic pathogen that causes local and disseminated diseases in immunosuppressed humans. Neutrophils play a critical role in the immune response against C. albicans and are continually present in the salivary fluid and in the blood. The aim of this study was to determine ageing-related changes in salivary and blood neutrophils and their potential implications in Candida-related denture stomatitis.     

Effect of Dim and Bright Light Exposure on Some Immunological Parameters Measured under Thermal Neutral Conditions

This study assesses the effects of ambient light conditions, under a thermoneutral environment, on selected immunological parameters of 7 healthy young women (aged 19 to 22 yrs). Subjects entered the bioclimatic chamber at 11∶00 h, controlled at 26°C and 60% relative humidity, a “neutral climate”. They lead a well‐regulated life in the climatic chamber (pre‐condition) while exposed to dim (200 lux) or, on the next day, bright (5000 lux) light between 06∶00 to 12∶00 h. Just before the end of each period of light exposure, a blood sample was taken for later immunological assay of white blood cell count (WBC), phagocytosis, interferon‐γ (IFN‐γ), interleukin‐4 (IL‐4), CD69 T cells (CD69), CD4⁺CD25⁺ T cells (CD4⁺CD25⁺), and transforming growth factor‐β 1 (TGF‐β1). The results, when compared with the pre‐condition, were as follows: 1) CD69 and IFN‐γ increased during normal conditions without thermal stress under dim light; 2) WBC increased and IL‐4 decreased under bright light; 3) as shown by the highly significant decrease of TGF‐β1, the immune system was activated under bright light; 4) phagocytosis tended to increase under bright light exposure; 5) CD69 and IFN‐γ were significantly higher, and CD4⁺CD25⁺ tended to decrease under bright light; 6) phagocytosis tended to be lower and TGF‐β1 significantly higher under dim light, indicating a decline of immune system function. Taken together, this preliminary single time‐point sampling study infers that some parameters are activated (CD69) while others are attenuated (phagocytosis, TGF‐β1) according to the environmental light intensity, dim vs. bright, in women adhering to a standardized routine in the absence of thermal stress. These findings are discussed in terms of inhibition of the sympathetic and excitation of the parasympathetic nervous system under the influence of life‐style regularity and daytime bright light exposure.     

Relationship between salivary histatin 5 levels and Candida CFU counts in healthy elderly

Objectives: Few epidemiological studies have confirmed the antifungal activity of histatin 5 in saliva against Candida species. The purpose of this study was to examine the relationship between concentrations of histatin 5 and the number of cultivable Candida in saliva samples from elderly. Methods: Whole saliva samples were obtained from 124 elderly people, 65 years or older, living in a rural community. The concentrations of histatin 5 in saliva samples were determined by the enzyme‐linked immunosorbent assay (ELISA) using a monoclonal antibody. Total colony‐forming units (CFUs) were counted on a selective medium for Candida. Multiple linear regression analysis was performed to determine the independent contribution of explanatory variables to Candida CFUs using age, sex, histatin 5 concentration and type of denture prosthesis as independent variables. Results: Saliva samples from 104 subjects (84%) were candidal colony‐positive. The youngest group (65–69 years old) showed significantly smaller Candida CFU counts than those in the older group. The mean Candida CFU count of denture wearers was significantly higher than that of non‐denture wearers. Significantly negative associations were found between Candida CFU counts and histatin 5 level in the oldest group (p < 0.05) and in the full‐denture wearers (p < 0.01). Multiple linear regression analysis revealed that Candida CFU counts were mostly associated with type of dentures, followed by histatin 5 concentration. Conclusion: Possible activity of histatin 5 against Candida in whole saliva of elderly people was epidemiologically confirmed. The area covered by the prostheses was a strong factor associated with the Candida CFU count.     

Effect of IL‐1β, PGE2, and TGF‐β1 on the expression of OPG and RANKL in normal and osteoporotic primary human osteoblasts

The RANKL/RANK/OPG pathway is essential for bone remodeling regulation. Many hormones and cytokines are involved in regulating gene expression in most of the pathway components. Moreover, any deregulation of this pathway can alter bone metabolism, resulting in loss or gain of bone mass. Whether osteoblasts from osteoporotic and nonosteoporotic patients respond differently to cytokines is unknown. The aim of this study was to compare the effect of interleukin (IL)‐1β, proftaglandin E₂ (PGE₂), and transforming growth factor‐β1 (TGF‐β1) treatments on OPG and RANKL gene expression in normal (n = 11) and osteoporotic (n = 8) primary osteoblasts. OPG and RANKL mRNA levels of primary human osteoblastic (hOB) cell cultures were assessed by real‐time PCR. In all cultures, OPG mRNA increased significantly in response to IL‐1β treatment and decreased in response to TGF‐β1 whereas PGE₂ treatment had no effect. RANKL mRNA levels were significantly increased by all treatments. Differences in OPG and RANKL responses were observed between osteoporotic and nonosteoporotic hOB: in osteoporotic hOB, the OPG response to IL‐1β treatment was up to three times lower (P = 0.009), whereas that of RANKL response to TGF‐β1 was five times higher (P = 0.002) after 8 h of treatment, as compared with those in nonosteoporotic hOBs. In conclusion, osteoporotic hOB cells showed an anomalous response under cytokine stimulation, consistent with an enhanced osteoclastogenesis resulting in high levels of bone resorption. J. Cell. Biochem. 110: 304–310, 2010. © 2010 Wiley‐Liss, Inc.     

Induction of cytokine formation by human intestinal bacteria in gut epithelial cell lines

Aims: To investigate the effects of human gut micro‐organisms on cytokine production by human intestinal cell lines. Methods and Results: Quantitative real‐time PCR assays were developed to measure the production of pro‐inflammatory (IL‐1α, IL‐6, IL‐18 and TNFα) and anti‐inflammatory (TGF‐β1, TGF‐β2, TGF‐β3, IL‐4 and IL‐10) cytokines in HT‐29 and Caco‐2 cell lines. They were co‐cultured with a range of mucosal bacteria isolated from ulcerative colitis patients, together with lactobacilli and bifidobacteria obtained from healthy people. HT‐29 cells were also co‐cultured with Campylobacter jejuni, enterotoxigenic Escherichia coli (ETEC), enteropathogenic E. coli and Salmonella typhimurium. The majority of commensal bacteria tested suppressed the expression of anti‐inflammatory cytokine mRNA, increased IL‐18, reduced IL‐1α, and with the exception of nonpathogenic E. coli, reduced TNF‐α. All overtly pathogenic species increased both pro‐inflammatory and anti‐inflammatory cytokine mRNA. Conclusion: Commensal and pathogenic species induced fundamentally different cytokine responses in human intestinal epithelial cell lines. Significance and Impact of the Study: Interactions between commensal bacteria tested in this study and the innate immune system were shown to be anti‐inflammatory in nature, in contrast to the pathogenic organisms investigated. These data contribute towards our understanding of how potential probiotic species can be used to suppress the pro‐inflammatory response in inflammatory bowel disease.     

Role of vitronectin and fibronectin receptors in oral mucosal and dermal myofibroblast differentiation

Background information. The activation of fibroblasts into myofibroblasts is a crucial event in healing that is linked to remodelling and scar formation, therefore we determined whether regulation of myofibroblast differentiation via integrins might affect wound healing responses in populations of patient‐matched HOFs (human oral fibroblasts) compared with HDFs (human dermal fibroblasts). Results. Both the HOF and HDF cell types underwent TGF‐β1 (transforming growth factor‐β1)‐induced myofibroblastic differentiation [upregulation of the expression of α‐sma (α‐smooth muscle actin)], although analysis of unstimulated cells indicated that HOFs contained higher basal levels of α‐sma than HDFs (P<0.05). Functional blocking antibodies against the integrin subunits α5 (fibronectin) or αv (vitronectin) were used to determine whether the effects of TGF‐β1 were regulated via integrin signalling pathways. α‐sma expression in both HOFs and HDFs was down‐regulated by antibodies against both α5 and αv. Functionally, TGF‐β1 inhibited cell migration in an in vitro wound model and increased the contraction of collagen gels. Greater contraction was evident for HOFs compared with HDFs, both with and without stimulation by TGF‐β1 (P<0.05). When TGF‐β1‐stimulated cells were incubated with blocking antibodies against α5 and αv, gel contraction was decreased to that of non‐stimulated cells; however, blocking αv or α5 could not restore cellular migration in both HOFs and HDFs. Conclusions. Despite intrinsic differences in their basal state, the cellular events associated with TGF‐β1‐induced myofibroblastic differentiation are common to both HOFs and HDFs, and appear to require differential integrin usage; up‐regulation of α‐sma expression and increases in collagen gel contraction are vitronectin‐ and fibronectin‐receptor‐dependent processes, whereas wound re‐population is not.     

Salivary tests associated with elderly people’s oral health

doi: 10.1111/j.1741‐2358.2012.00627.x Salivary tests associated with elderly people’s oral health Introduction: The saliva constitutes essential condition for the individual’s health. Aim: Identify the relation of the salivary flow and saliva pH with medicine use and oral discomfort in elderly. Methods and materials: Cross‐sectional study with 68 elderly living in a long staying institution. Salivary tests were performed based on Bo Krasse’s methodology. For pH, the Universalindikator – Merck tape was used. A questionnaire was applied, organising data through Software SPSS version 17. Pearson’s qui‐square distribution, Fisher’s exact test and t‐test for paired data were used, with significance level of 5% and confidence interval of 95%. Results: Among the 68 elderly (average of 70.4 years, SD ± 7.27), 80% showed normal pH. The rate of salivary flow was as follows: very low, 32.3%; lowered, 41.2%; and normal, 25.5%; 30.9% reported dry mouth; 22.1% problems with taste; 17.6%, dysphagia; and 14.7%, burning mouth. 76.5% used medicines. There was statistical significance between medicine use and dry mouth (p = 0.015). They showed an association between salivary flow and medicine use (p = 0.048), feels dry mouth (0.018) and difficulty to swallow (p = 0.046), and saliva pH without stimulation and feels dry mouth (p = 0.003), difficulty to swallow (p = 0.006) and burning mouth sensation (p = 0.014). Conclusion: Low salivary flow and saliva pH interfere on elderly people’s health and medicine use influences on results.     

Relative roles of TGF‐β1 and Wnt in the systemic regulation and aging of satellite cell responses

Muscle stem (satellite) cells are relatively resistant to cell‐autonomous aging. Instead, their endogenous signaling profile and regenerative capacity is strongly influenced by the aged P‐Smad3, differentiated niche, and by the aged circulation. With respect to muscle fibers, we previously established that a shift from active Notch to excessive transforming growth factor‐beta (TGF‐β) induces CDK inhibitors in satellite cells, thereby interfering with productive myogenic responses. In contrast, the systemic inhibitor of muscle repair, elevated in old sera, was suggested to be Wnt. Here, we examined the age‐dependent myogenic activity of sera TGF‐β1, and its potential cross‐talk with systemic Wnt. We found that sera TGF‐β1 becomes elevated within aged humans and mice, while systemic Wnt remained undetectable in these species. Wnt also failed to inhibit satellite cell myogenicity, while TGF‐β1 suppressed regenerative potential in a biphasic fashion. Intriguingly, young levels of TGF‐β1 were inhibitory and young sera suppressed myogenesis if TGF‐β1 was activated. Our data suggest that platelet‐derived sera TGF‐β1 levels, or endocrine TGF‐β1 levels, do not explain the age‐dependent inhibition of muscle regeneration by this cytokine. In vivo, TGF‐β neutralizing antibody, or a soluble decoy, failed to reduce systemic TGF‐β1 and rescue myogenesis in old mice. However, muscle regeneration was improved by the systemic delivery of a TGF‐β receptor kinase inhibitor, which attenuated TGF‐β signaling in skeletal muscle. Summarily, these findings argue against the endocrine path of a TGF‐β1‐dependent block on muscle regeneration, identify physiological modalities of age‐imposed changes in TGF‐β1, and introduce new therapeutic strategies for the broad restoration of aged organ repair.     

Correlation between factors associated with the removable partial dentures use and Candida spp. in saliva

doi: 10.1111/j.1741‐2358.2010.00390.x
Correlation between factors associated with the removable partial dentures use and Candida spp. in saliva Objectives: To correlate the presence and number of Candida spp. in the saliva of wearers of removable partial dentures retained with precision attachments with the proportion of metal/acrylic resin present in the dentures. Methods: Saliva samples from 40 removable partial denture wearers (test) and one paired sample of individuals, non‐wearers of any type of removable denture (control) were collected, seeded, and the colony forming units of Candida counted and identified. The metal/acrylic resin proportion of each denture was quantified, using silicone plates pressed over each denture. Results: Candida spp. was found in the saliva of 80% of the individuals in the test group and 65% of the control, with C. albicans being the most prevalent species. The test group presented with the highest number of colony forming units of Candida per ml of saliva, and there was weak correlation between this number and the metal and resin area of the denture (Pearson’s coefficient of correlation). Greater prevalence and a higher number of colony forming units of Candida per ml of saliva occurred in removable partial denture wearers (p = 0.04) with a weak positive correlation between the metal and resin area and the number of colony forming units of Candida per ml of saliva. However, this correlation was more significant for the area of resin.     

Clinical and microbiological efficacy of three different treatment methods in the management of denture stomatitis

Gerodontology 2010; doi: 10.1111/j.1741‐2358.2009.00354.x
Clinical and microbiological efficacy of three different treatment methods in the management of denture stomatitis Objective: This study evaluated. the effect of mouthrinses and tissue conditioner on the clinical findings and microbial flora of 60 patients with Newton’s type II denture stomatitis (N2DS) Background: Denture stomatitis is a common problem in complete denture wearers. Materials and methods: Sixty patients with N2DS were included in this study and divided into three groups. Two groups of patients were instructed to rinse their mouth with the designated mouthrinses DioxiDent and Corsodyl twice daily for 1 min and to soak their dentures overnight in these solutions for 15 days. For the third group, tissue conditioner was placed in each of 20 patients’ existing maxillary dentures. Patients were evaluated both clinically and microbiologically at baseline and after 15 days. Palatal swabs and smears were taken from each patient before and after treatment and these samples were examined mycologically. The difference between Candida colonisation before and after treatment and the differences between pre‐treatment and post‐treatment clinical findings were assessed. Results: DioxiDent and Corsodyl showed an improvement in palatal inflammation and a decrease in Candida colonisation compared to Visco‐gel. Conclusions: The effectiveness of topical chlorine dioxide and chlorhexidine gluconate in the management of N2DS was demonstrated.     

Aggregatibacter actinomycetemcomitans outer membrane protein 29 (Omp29) induces TGF‐β‐regulated apoptosis signal in human gingival epithelial cells via fibronectin/integrinβ1/FAK cascade

Gingival junctional epithelial cell apoptosis caused by periodontopathic bacteria exacerbates periodontitis. This pathological apoptosis is involved in the activation of transforming growth factor β (TGF‐β). However, the molecular mechanisms by which microbes induce the activation of TGF‐β remain unclear. We previously reported that Aggregatibacter actinomycetemcomitans (Aa) activated TGF‐β receptor (TGF‐βR)/smad2 signalling to induce epithelial cell apoptosis, even though Aa cannot bind to TGF‐βR. Additionally, outer membrane protein 29 kDa (Omp29), a member of the Aa Omps family, can induce actin rearrangements via focal adhesion kinase (FAK) signalling, which also plays a role in the activation of TGF‐β by cooperating with integrin. Accordingly, we hypothesized that Omp29‐induced actin rearrangements via FAK activity would enhance the activation of TGF‐β, leading to gingival epithelial cell apoptosis in vitro. By using human gingival epithelial cell line OBA9, we found that Omp29 activated TGF‐βR/smad2 signalling and decreased active TGF‐β protein levels in the extracellular matrix (ECM) of cell culture, suggesting the transactivation of TGF‐βR. Inhibition of actin rearrangements by cytochalasin D or blebbistatin and knockdown of FAK or integrinβ1 expression by siRNA transfection attenuated TGF‐βR/smad2 signalling activity and reduction of TGF‐β levels in the ECM caused by Omp29. Furthermore, Omp29 bound to fibronectin (Fn) to induce its aggregation on integrinβ1, which is associated with TGF‐β signalling activity. All the chemical inhibitors and siRNAs tested blocked Omp29‐induced OBA9 cells apoptosis. These results suggest that Omp29 binds to Fn in order to facilitate Fn/integrinβ1/FAK signalling‐dependent TGF‐β release from the ECM, thereby inducing gingival epithelial cell apoptosis via TGF‐βR/smad2 pathway.     

Primary human muscle precursor cells obtained from young and old donors produce similar proliferative,differentiation and senescent profiles in culture

The myogenic behaviour of primary human muscle precursor cells (MPCs) obtained from young (aged 20–25 years) and elderly people (aged 67–82 years) was studied in culture. Cells were compared in terms of proliferation, DNA damage, time course and extent of myogenic marker expression during differentiation, fusion, size of the formed myotubes, secretion of the myogenic regulatory cytokine TGF‐β1 and sensitivity to TGF‐β1 treatment. No differences were observed between cells obtained from the young and elderly people. The cell populations were expanded in culture until replicative senescence. Cultures that maintained their initial proportion of myogenic cells (desmin positive) with passaging (n = 5) were studied and compared with cells from the same individuals in the non‐senescent state. The senescent cells exhibited a greater number of cells with DNA damage (γ‐H2AX positive), showed impaired expression of markers of differentiation, fused less well, formed smaller myotubes and secreted more TGF‐β. The data strongly suggest that MPCs from young and elderly people have similar myogenic behaviour.     

Hierarchical interactions among cytokines establish the functional state of microglia

Microglia rapidly respond to CNS injury yet the mechanisms leading to their activation and inactivation remain poorly defined. In particular, few studies have established how interactions among inflammatory mediators affect the innate immune response of microglia. To begin to understand the hierarchy of cytokine signalling we examined the effects of several cytokines on purified newborn and adult rat microglia in vitro, and we have examined the microglial response to injury in mice deficient in the IL‐1 type 1 receptor (IL‐1R1). Using several indices of activation, we find that IL‐1β, TNF‐α, and IL‐6 are potent microglial activators. By contrast, TGF‐β1 did not activate the cells and when TGFβ1 was administered prior to IL‐1β, it blocked the effects of IL‐1β. However, TGFβ1 was ineffective in antagonizing IL‐6. In null mice lacking the IL‐1R1, microglia inefficiently responded to injury, and IL‐6 induction was severely curtailed. These data establish a model of hierarchical signalling, whereby constitutive expression of TGF‐β1 in the CNS maintains microglia in a resting state. IL‐1, while an important microglial activator, is modifiable, whereas, the downstream cytokine, IL‐6, is a strong stimulus that is unaffected by other modifiers of the innate immune response. Acknowledgements: Supported by NMSS award #RG 3837.     

Issue information

Galectin‐3 (Gal‐3) plays a critical role in vascular inflammation and fibrosis. The role of TGF‐β1 in mediating pulmonary vascular fibrosis is well documented; thus, we suspected that Gal‐3 could be an important factor in TGF‐β1‐induced fibrosis in pulmonary adventitial fibroblasts (PAFs). We treated rats with monocrotaline (MCT) and cultured PAFs with TGF‐β1 to stimulate fibrosis. We found that MCT injection induced vessel thickening and extracellular matrix deposition in vivo. TGF‐β1 stimulated the production of collagen and fibronectin (Fn) protein in vitro. TGF‐β1 promoted the expression of Gal‐3 and its translocation, while silencing Gal‐3 reduced Col‐1a deposition. Blockage of STAT3 decreased the expression of Gal‐3 induced by TGF‐β1. Gal‐3 increased Col‐1a accumulation and downregulated matrix metallopeptidase 9 (MMP‐9) expression in PAFs, but it did not affect Fn expression. These findings demonstrate that Gal‐3 is required for TGF‐β1‐stimulated vascular fibrosis via a STAT3 signaling cascade and that MMP‐9 is also involved in TGF‐β1/Gal‐3‐induced vascular fibrosis.     

Clinically acceptable restorations may be a hotbed for cariogenic microbes

doi: 10.1111/j.1741‐2358.2011.00571.x Clinically acceptable restorations may be a hotbed for cariogenic microbes Objective: The aim of this study was to investigate the cross‐sectional association of dental restorations with salivary cariogenic pathogens among the elderly to establish effective parameters of caries risk for this population. Materials and methods: Stimulated whole saliva was collected from 289 community‐dwelling older adults (66.2 ± 3.9 years old) who had 20 or more teeth. Salivary levels of three cariogenic bacteria (Streptococcus mutans, Streptococcus sobrinus and lactobacilli) were estimated using quantitative polymerase chain reaction (real‐time PCR) method. Results: The mean number of residual teeth was 26.4, and restored teeth with crowns, inlays and composite resin were 7.35, 3.88 and 0.68, respectively. The number of crowns correlated positively with salivary S. mutans, S. sobrinus and lactobacilli. Multiple linear regression analyses showed that the number of restored teeth with crowns was independently associated with salivary S. mutans, S. sobrinus and lactobacilli after controlling for age, gender, number of residual teeth and salivary flow rate. Salivary flow rate was independently associated with salivary S. mutans and lactobacilli. Conclusion: The number of crowns had an association with salivary levels of cariogenic bacteria, suggesting that this parameter may be a caries risk indicator for the elderly population.     

TGF‐beta signalling in the adult neurogenic niche promotes stem cell quiescence as well as generation of new neurons

Members of the transforming growth factor (TGF)‐β family govern a wide range of mechanisms in brain development and in the adult, in particular neuronal/glial differentiation and survival, but also cell cycle regulation and neural stem cell maintenance. This clearly created some discrepancies in the field with some studies favouring neuronal differentiation/survival of progenitors and others favouring cell cycle exit and neural stem cell quiescence/maintenance. Here, we provide a unifying hypothesis claiming that through its regulation of neural progenitor cell (NPC) proliferation, TGF‐β signalling might be responsible for (i) maintaining stem cells in a quiescent stage, and (ii) promoting survival of newly generated neurons and their functional differentiation. Therefore, we performed a detailed histological analysis of TGF‐β1 signalling in the hippocampal neural stem cell niche of a transgenic mouse that was previously generated to express TGF‐β1 under a tetracycline regulatable Ca‐Calmodulin kinase promoter. We also analysed NPC proliferation, quiescence, neuronal survival and differentiation in relation to elevated levels of TGF‐β1 in vitro and in vivo conditions. Finally, we performed a gene expression profiling to identify the targets of TGF‐β1 signalling in adult NPCs. The results demonstrate that TGF‐β1 promotes stem cell quiescence on one side, but also neuronal survival on the other side. Thus, considering the elevated levels of TGF‐β1 in ageing and neurodegenerative diseases, TGF‐β1 signalling presents a molecular target for future interventions in such conditions.     

The role of TGF‐β1/Smad2/3 pathway in platelet‐rich plasma in retarding intervertebral disc degeneration

Recent studies have suggested that platelet‐rich plasma (PRP) injections are an effective way to retard intervertebral disc degeneration, but the mechanism of action is unclear. Activated platelets release some growth factors, such as transforming growth factor‐β1 (TGF‐β1), which positively modulate the extracellular matrix of nucleus pulposus cells. The purpose of this study was to explore the mechanism underlying the PRP‐mediated inhibition of intervertebral disc degeneration. In an in vitro study, we found that the proliferation of nucleus pulposus cells was greatly enhanced with 2.5% PRP treatment. The TGF‐β1 concentration was much higher after PRP treatment. PRP administration effectively increased the collagen II, aggrecan and sox‐9 mRNA levels and decreased collagen X levels. However, Western blotting demonstrated that specifically inhibiting TGF‐β1 signalling could significantly prevent nucleus pulpous cellular expression of Smad2/3 and matrix protein. In a rabbit study, magnetic resonance imaging revealed significant recovery signal intensity in the intervertebral discs of the PRP injection group compared with the very low signal intensity in the control groups. Histologically, the PRP plus inhibitor injection group had significantly lower expression levels of Smad2/3 and collagen II than the PRP group. These results demonstrated that a high TGF‐β1 content in the platelets retarded disc degeneration in vitro and in vivo. Inhibiting the TGF‐β1/Smad2/3 pathway could prevent this recovery by inactivating Smad2/3 and down‐regulating the extracellular matrix. Therefore, the TGF‐β1/Smad2/3 pathway might play a critical role in the ability of PRP to retard intervertebral disc degeneration.     

Antagonizing peroxisome proliferator‐activated receptor γ facilitates M1‐to‐M2 shift of microglia by enhancing autophagy via the LKB1–AMPK signaling pathway

Microglia‐mediated neuroinflammation plays a dual role in various brain diseases due to distinct microglial phenotypes, including deleterious M1 and neuroprotective M2. There is growing evidence that the peroxisome proliferator‐activated receptor γ (PPARγ) agonist rosiglitazone prevents lipopolysaccharide (LPS)‐induced microglial activation. Here, we observed that antagonizing PPARγ promoted LPS‐stimulated changes in polarization from the M1 to the M2 phenotype in primary microglia. PPARγ antagonist T0070907 increased the expression of M2 markers, including CD206, IL‐4, IGF‐1, TGF‐β1, TGF‐β2, TGF‐β3, G‐CSF, and GM‐CSF, and reduced the expression of M1 markers, such as CD86, Cox‐2, iNOS, IL‐1β, IL‐6, TNF‐α, IFN‐γ, and CCL2, thereby inhibiting NFκB–IKKβ activation. Moreover, antagonizing PPARγ promoted microglial autophagy, as indicated by the downregulation of P62 and the upregulation of Beclin1, Atg5, and LC3‐II/LC3‐I, thereby enhancing the formation of autophagosomes and their degradation by lysosomes in microglia. Furthermore, we found that an increase in LKB1–STRAD–MO25 complex formation enhances autophagy. The LKB1 inhibitor radicicol or knocking down LKB1 prevented autophagy improvement and the M1‐to‐M2 phenotype shift by T0070907. Simultaneously, we found that knocking down PPARγ in BV2 microglial cells also activated LKB1–AMPK signaling and inhibited NFκB–IKKβ activation, which are similar to the effects of antagonizing PPARγ. Taken together, our findings demonstrate that antagonizing PPARγ promotes the M1‐to‐M2 phenotypic shift in LPS‐induced microglia, which might be due to improved autophagy via the activation of the LKB1–AMPK signaling pathway.     

In vivo assessment of the effect of an adhesive for complete dentures on colonisation of Candida species

doi: 10.1111/j.1741‐2358.2009.00345.x
In vivo assessment of the effect of an adhesive for complete dentures on colonisation of Candida species Objective: Denture adhesives have long been recognised by denture wearers as a useful adjunct to denture retention and stability. The objective of the present study was to evaluate, in vivo, the effect of a denture adhesive on oral quantities of Candida species by determination of absolute counts of colony‐forming units (CFU) per ml of saliva of individuals who use this denture adhesive for a period of 14 days. Materials and methods: Twenty‐four individuals were randomised in two equal groups of 12 (test and control), with the individuals of the test group using the adhesive for 14 days. Samples of saliva were collected from all individuals on days 0 (initial), 7 and 14. Aliquots of saliva were diluted and plated in duplicate on Sabouraud dextrose agar with chloramphenicol and incubated for 37°C for 48 h, the CFU/ml were counted in the individuals of each group and the data of each group were compared at the different time periods and analysed statistically by the non‐parametric Mann‐Whitney U‐test (α ≤ 5%). Results: There were no statistically significant differences between the test and control groups during the test periods. Conclusion: Within of the limitations of this study, the data suggested that the denture adhesive tested did not significantly alter the oral microbiota during the 14‐day trial period.